Radio relay and distribution system



April 25, 1939.

A. N. GOLDSMITH RADIO RELAY AND DISTRIBUTION SYSTEM APPARATUS W6 APPARATUS FREQUENCY cx/wamfoe DEMOLJUL/WOP) ,4/1/0 POWER AMFL/F/L-R Filed Dec '7, 1936 3 Sheets-Sheet l Fig.2

2/ FREQUENCY POWER TUNER CHANGER AMPLIFIER POWER AMPLIFIER CODE TL/IVER SELECTOR AMPLIFIER POWER AMPLIFIER POWER 47 FREQUENCY CHANGER AND AMPLIFIER A/VD AMPL IF/ERS INVENTOR ALFRED N. GOLDSMITH ATTORNEY April 25, 1939.

A. N. GOLDSMITH 2,155,821 RADIO RELAY AND DISTRIBUTION S YSTEM Filed Dec. 7, 1936 3 Sheets-Sheet 2 3 Fmu mar/ME ATTORNEY April 25, 1939.

A. N. GOLDSMITH 2,155,821 RADIO RELAY AND DISTRIBUTION SYSTEM Filed Dec. 7, 1956 3 Sheets-Sheet 3 1 3 13 POWER I37 132 AMPLIFIER coMMolv A AMPLIFIER 4 52-25 NON-DIRECTIONAL SWITCHES ANTENNA X j TRANSMITTING ANTENNAFY FREQUENCY CHANGERS INVENTOR ALFRED N 020M117 BY Ad w ATTORNEY Patented Apr. 25, 1939 v FFHCE RADIO RELAY AND DISTRIBUTION SYSTEM Alfred N. Goldsmith, New York, N. Y. Application December 7, 1936, Serial No. 114,536

17 Claims.

This invention relates to methods and systems of radio inter-communication by means of as- Y sociated transmitting and receiving stations intermediate relay stations. The system herein disclosed is particularly useful with short wave and ultra-short wave channels. By relay station it will be understood that I refer to any one of a series of stations, each of which is adapted to pick up a communication transmitted from a preceding station in a sequence, and after amplification of the signal 'to re-transmlt the same or, if desired, to broadcast it from that station. In a network of such relay stations it is often desirable that reception be had on directional beams and that re-transmission of the sigby means of a sharply concentrated beam of energy.

In general, such relay systems will operate on ultra-high frequencies with directional transmission and reception, for reasons connected with the eificiency of utilization of the radio frequency energy, the wide frequency bands transmissible, and the relatively undistorted propagation. For related reasons, the ultra-short waves and. the so-called micro-waves (below about 1 meter in length) are believed to be the most suitable for directed beam radio relay systems. It is well known that such extremely short waves can be conveniently radiated and received directionally.

Within each such station there should be at least one device:namely, a power amplifier which is capable of enhancing the energy of the received signal while retaining its intelligence carrying capabilities substantially undisturbed. The incoming signal is fed in one form or another into the power amplifier in question, and the output of the amplifier is in turn fed into the transmitting antenna of the station, then to be radiated toward the next relay station of the sequence or system. There are many detailed arrangements possible of eifective use within the station and built around the power amplifier in question.

Some of these arrangements include, for example, the provision of a selective and a sensitive radio frequency receiver for selection and control of the incoming signal, in other words, a monitor receiver having preferably a station selector and switching device remotely controlled for rendering the relay station operative in any desired manner so as to relay the signals in one direction or another or to broadcast the same. An important part of the relay station is means for changing the frequencies from that of the incoming carrier wave to any difierent carrier wave frequency to be used in directionally re-transmitting or in broadcasting.

amplifiers whereby the relay station may be caused to re-transmit 'over any one or over a selected plurality of different channels.

It is a further object of my invention to provide a relay station in which communications or signals may be injected locally and transmitted optionally in any desired direction or broadcast from that station.

It is a iurtherobject of my invention to provide a relay station in combination with other being broadcast from any stations.

It is another object of my invention to provide a system of relay stations which may be arranged either in a concatenation or closed loop, otherwise be entire system being so co-ordinated that a communication may be established between any two or more stations either one-way or two-way.

The foregoing and other objects .and advantages of my invention will become apparent upon consideration of the following detailed description of the methods which may be adopted, as well as certain types of apparatus that may be employed, the description to energy;

Fig. 2 shows diagrammatically an arrangement of apparatus at a relay station including both directional and non-directional antennas;

Fig. 3 shows a simple arrangement for re-transone or more of said iittinga received signal both directionally and on-directionally at the same time;

Fig. 4 is a modification of the system shown 1 Fig. 3, but in this case having separate power mplifiers for the energy to be broadcast and for hat which is directionally re-transmitted, repectively;

Fig. 5 shows a system for simultaneous recepion and re-transmission of two communications, me of which may be received on a non-directional intenna and re-transmitted directionally, while ;he other communication is received directionally and then simultaneously broadcast from the nonlirectional antenna and radiated from a directional beam antenna;

Fig. 6 shows means for performing a combination of functions of systems shown in the preceding figures;

Fig. 7 shows in considerable detail a preferred embodiment of apparatus at a relay station for remotely controlling the same;

Fig. 8 shows a modification of my invention in which the relay station is provided with a power amplifier into which signaling energy may be injected through suitable frequency changers from any selected source and then re-transmitted in any desired direction or impressed upon a broadcasting antenna at will;

Fig. 9 illustrates a system of relay stations arranged in a closed loop:

Fig. 10 shows a network of relay stations, two channels of which are caused to intersect one another;

Fig. 11 shows a detail oi a selecting mechanism;

Fig. 12 shows a modification using filters between a power amplifier and difierent directive antennae; and

Fig. 13 shows an embodiment of a relay station.

Referring first to Fig. 1, I show an antenna system which is suitable for simultaneous transmission and reception. The dipole antenna d is disposed at the focus of a reflector i, having preferably a paraboloidal contour. Another dipole antenna 5 is also disposed at a focus of a similar reflector 2. Between these'two antenna systems I may, if desired, employ shielding means 8 so as to maintain the transmitting and receiving systems independent of one another. The arrangement can manifestly be used for double transmission or double reception if desired. The axes of the paraboloids i and 2 may be inclined at any suitable angle if required by the directions of transmission and reception, respectively.

While Fig. 1 shows one arrangement whereby the object of my invention may be carried out, it is to be understood that any other arrangement of the antennas which will accomplish the same result may be utilized as an alternative. It is, of course, to be understood that I may also em-= ploy at any one relay station as many of these directional antennas as would be required for directing the transmitted energy eficiently to other stations as well as to efiiciently collect the received energy from other stations. I may also use omnidirectional antennas in such a relay station both for reception and for broadcasting.

Fig. 2 shows a. combination of a plurality of di rectional antennas such as shown in Fig. l and a non-directional receiving antenna 2i. The directional receiving antenna 28 is connected to a power amplifier 21 whence energy may be impressed upon a radiating antenna 26 in one portion of a directional transmitting antenna. Signals may be simultaneously received on the non through the switch directional antenna 2i and passed through successive stages of tuning, frequency changing and amplification (as shown in portions 22, Hand 2d, respectively, of the block diagram) and thence may be directionally radiated from the antenna 25. Preferably the two antennae 25 and 2% would be disposed at the focus of the paraboloidal reflector I, 2, the same as the dipoles 4 and 5 as shown in Fig. 1. In order to avoid confusion, however, the antennae 25 and 26 have been illustrated as though slightly displaced from this focus.

Fig. 3 shows in the simplest possible manner the use of my invention in a relay station for amplifying at 3| the received directional signal as collected by the antenna 30, the amplifier 3i being serviceable both to re-broadcast the signal on the non-directional antenna 33 while transmitting the signal further on a directional beam by means or the antenna 32.

A modification of the system of Fig. 3 appears in Fig. 4. Here the receiving directional antenna has two dipoles and II. The dipole 48 is connected to its appropriate power amplifier 42, the output from which may be applied to a transmitting directional antenna 43. The energy received on the directional antenna 4i may be simultaneously impressed through stages of tuning at 643, and after connecting the tuner with a power amplifier 86 through a code selector 45, the signals may be broadcast from the non-directional antenna fl'i. In this case, however, the power amplifier Q6 normally stands disconnected, but after the reception of a. code signal for controlling the code selector Q5, connection is then made to the power amplifier and the latter is started up.

The modification of my invention shown in Fig. 5 serves to satisfy the conditions in which it may be desirable to combine omni-directional reception with signals directionally received and to re-transmit the same directionally while broadcasting only the signals that come in on a directional beam. In this case it is possible to maintain two distinct channels of communication between the non-directional and the directional systems, use being made of diflerent carrier frequencies. Thus the apparatus which receives the directional signal on antenna 5i may employ a frequency changer so as to re-broadcast the signal on the antenna 56 at, say, frequency f1.

The apparatus at 51 may, however, be arranged to change the frequency of the signal received on the non-directional antenna 58 so that this signal will now go out from the directional transmitting antenna 54 on the same frequency as that of the frequency changer and power amplifier shown at 52, where the incoming signal picked up on the receiving antenna 58 would be transferred to the directional transmitting anterms. 63.

Referring to Flg.,6, I show a combination of directional and non-directional antennae suit.- able for two-way communications and for receiving or transmitting omni-directionally as well. The arrangement shown is merely illustrative of a variety of alternative combinations. Assuming that it may be desired to re-transmit signals picked up on the directional receiving antenna 60, these signals can be passed through the frequency changer and amplifier 64 and applied to the directional transmitting antenna 65. If broadcasting of the signal is to be desired from this station the energy collected on the. directional antenna Bi may be passed 68 and after frequency changing and power amplification at 82 may be sent out on the non-directional antenna 63. All of this may be accomplished simultaneously with the reception and re-transmission of signals in a direction opposed to that of the directional signals Just previously mentioned. Thus signals the directional antenna 86, and after frequency changing and amplificare-transmitted directionally Fig. 7 illustrates a means and a method for controlling a typical relay station such as has been described in the foregoing part of the specification. The arrangement will be understood to be suggestive of various modifications wherein a station selector may be employed for remotely controlling the connections between diflerent elements of the relay station.

Generally speaking it is desirable that the relay station be made entirely automatic in its operation so that it may respond to selecting and controlling signals transmitted from a remote point. Accordingly it is necessary that there should be a monitor receiver, at all times stations.

The combination shown in Fig. 7 is indicated as pertaining to station B. It is provided with directional receiving antennae 14 and 15 by be picked up emciently from station A and station C respectively, these stations being understood to be of the same type as station B shown in the diagram. The antennas 14 and 15 are represented as associated with focusing reflectors of the same type as shown in Fig. 1 in order that directive beams may be efiiciently received.

Each relay station such as station B is also provided with a plurality of transmitting antennae such as 18 and 11 each aimed toward one or another of the relay stations with which communication is to be established.

The omni-directional receiver 72, when it responds to selective signals for controlling the Witching arrangements, will pass these signals through one or another of two filters 18 and 19., according to the modulating frequencies that may be employed for selective and controlling functions. Thus filter 18 may pass impulses of frequency f1 into a station selector 80. One detail of the mechanism to be employed in the station selector 80 may be according to Fig. 11 which shows a rotary switch 59, of conventional type such as commonly used in automatic telelation frequency f1 and when the rotary switch has taken one step it closes a circuit from battery 8! through relay 82. This operation prepares a circuit for a subsequent controlling opration to be derived from the reception of further selective signals, say of a modulation frequency f2.

. Assuming now that certain desired connections 5 are to be made between receiving and re-transmitting 20 of the movable contactor.

Depending upon nections that is at magnet 83 sive impulses through the 25 of frequency f2 which 40 are receivable at station Each of the switches under control of the motor magnets 85, 86 and 81 respectively is arranged to establish one or more appropriate frequency changer or demodulator 45 alone will be made responsive to the final group 50 er t9 and thence to the modulator 9| for modu- 51! member 94 has been moved two 60 simultaneously on two directive beams, one to then re-transmission will wards station A.

Assuming now that. a communication is to be in parallel with either the motor magnet 88 or station B would berequired to one or more of.

the motor magnet 81, or it may be operatedindependently of the others. The manner operation is in all cases determined by the position of the switch member 86 on the step-by-step switch that is controlled by the motor magnet 88. Thus' when the motor magnet 89 has responded to two impulses, then the member 86 establishes connections to switch magnets 85 and 86 simultaneously. When the switch member 8 moves the motor magnet 86 operates solo. When switch member as moves four steps, motor magnets 85, 8S, and 8t operate simultaneously. When switch member 86 moves five steps, motor magnets 85 and ill operate simultaneously. when the switch member til moves six steps motor magnet t'l operates solo, and when switch member 86 moves seven steps, motor magnet 85 operates solo.

Each of the switches for final selection has connections with different frequency changers 8t, 99 and 39 respectively so that communications may be handled from any given source as from the omni-directional reception on antenna it or from station A as received on antenna M or from -rials picked up on cyhasX aisaeai frequency fa so as to advance one or more of the rotary switch members at, we or it! beyond the previous setting point. Thus it is possible to provide any individual settings for these switch members 84, I00 and i0! independently oi! one another.

To give an example of how the system may be employed according to the ioregoing description, let it be assumed that omni-directional sigantenna It are to be re-transmitted on the directional antenna 1! to station 0 and at the same time directional signals received from station C on antenna 15 are to be re-transmitted to station A from antenna 16. The operation of controlling the rotary switches may be summarized by designating impulses of frequenand. impulses of I: as Y. The following tabulation shows the reception of a complete code signal for making the assumed connections and beneath each designation of an X-impulse or a Y-impulse, as received in the proper sequence, the operation of the system is explained. This table shows where the selector switch 59 is operated in response to the reception of an X-impulse. One of the relays 82, S9 and use becomes energized with successive forward movements of the selector switch 59. Thus circuits are prepared to the several rotary switch motor magnets and the release magnets. The operation of the rotary switches to advance their connectors by successive forward steps is shown and when the final connections are made from one antenna to another. In the last two columns I show the operation of the selector switch so and of the reset magnet W6 after termination of the prostation 0 as received on antenna it. The switchgrain which is to be relayed:

Impulse -.xYYYYYxYxYxYYxY Seiectorswitch ..I.- 59 59 59 59 59 Relayenergized 82 ...l 69 82 69 105 Circuitpreparedtomagnetuiun. 83 gig..." at s1 10a Connectorswitcll s4 s4 s4 s4 s4 s4 101 101 Forwardst/eps 1 2 3 4 5 1 6 2 3 Circuit made:

rom 73 75 To 77 76 Re-set magnets s ing arrangements are provided by the rotary switches whose movable contactors 94, I08 and i0! are shown under control of the motor magnets 85, 86 and 81 respectively. p

In order to provide for occasions when the relay handle two independent communications simultaneously and to re-transmit them in different directions or one of them as an omni-directional broadcast, I preferably arrange'the switch 59 in the station selector Bil as shown in Fig. 11. After operating the rotary switch magnets 85, and 8'! to advance their rotary switches one or two steps, a succeeding impulse of frequency f1 may be.employed to advance the switch another step thereby to de-energize relay 69 and to re-energize relay 82. Thus the motor magnet 83 may be caused to step its switch member 84 forward into a further position in response to signals of frequency f2. After this operation the switch 59 may againbe moved forward for reenergizing relay 69 thereby to permit of the em-- ployment of a final group of selecting impulses of It will thus be seen that whether the reception is directive or non-directive it can be retransmitted in a desired one or more directions to associated relay stations, or it may be broadcast. Furthermoraa combination of directive transmission and broadcasting can be had if desired. When such is the case then switch members 94 Hill and IM, or any of them, may be moved into a position two steps away from the homing position thereby to include in the connections from the operative frequency changer a circuit to the modulator 92 which modulates the output from an oscillator I92 and passes the same through an amplifierv I03. Hence it may be broacast from the omni-directional antenna Nil.

Assuming now that a communication has been relayed by station B and that this station is subsequently to be closed down, it is then necessary to transmit one or more final impulses of frequency f1 such as to be filtered when received on the monitor receiver I2 through the device 18 and thenceto the station selector 80. This operation is for the purpose of stepping forward the rotary switch 59 to its most advanced position where it closes a circuit for energizing relay I05. Thisrelay when operated prepares a circuit from the filter-rectifier 19 to a plurality of releasing magnets I06 each of which is associated with one of the rotary step-by-step switches described in the foregoing. As shown in the diagram there are four such switches each having a release magnet IOG. The releasing operation, therefore, is made responsive to a fin'al shut-down signal having a modulation frequency fa or, if desired, the restoration of all of the rotary switches can be made to result merely from the reception of a final impulse of frequency ii. In this case .the armature I01 may be fed with energy from the battery 8| without passing through the rectifier 19.

Another modification of my invention is shown in Fig. 3, the feature of which is the employment of a single power amplifier III) with switching arrangements both on the input side and .on

itself to economy of equipment because obviously the power amplifier can be used selectively in the circuit between any one of the receivers of the relay station and any one or more of the transmitters thereof.

The modification in Fig. 8 includes illustratively certain of the elements shown in Fig. 7 and others as well. Thus directive receiving antennae l4 and 15 are shown, the same as in Fig. 7. Also transmitting antennae I6 and H are the same as shown in Fig. '7. The omni-directional receiving antenna 13 is the same, and likewise the omni-directional transmitting antenna I04 is the same. Additional to these receiving and transmitting antennae any further receiving and transmitting equipment may be provided such as a directive receiving antenna Ill and a directive transmitting antenna H2, both being aimed toward station E.

The details of the switching arrangements may be analogous to those shown in Fig. 7, but with provision for additional combinations since there are more units to be selectively controlled either individually or in difierent combinations. The development of the idea shown in Fig. 7 will be readily understood by those skilled in the art insofar as the requirements of the organization shown'in Fig. 8 are concerned. Accordingly a switching system is represented generally in the block diagram H3 for establishing connections between any one or any plurality of the frequency changers 89, 99, I09 and H respectively, and when such connections are established the can be applied to the power demodulation energy or energy of a suitable modulation frequency. This power amplifier has an input circuit H5 and an output circuit H8. There is also shown a local substation H8 which is connected to the output circuit from the switching system M3 by a conductor H7. The microphone N9 of this sub-station is preferably connected through a conductor H213 to the input side of the power amplifier Hi3.

In some of the modifications of my invention as herein shown and described a local oscillator has been included in the relay system in combination with a modulator. The incoming modulated carrier wave frequency, after demodusome different carrier frequency. This arrangement may not always be desirable, so that This arrangement lends in the interest oi economy, particularly in the use of directed beams of ultra-short waves. it is quite within the scope of my invention to re- The receiving antennae l3! and bly aimed in different directions for receiving two stood to be transmissible on the same carrier In the modification shown at Fig. 8 provision is made not only for remote control of the station selector 80 and of the switching system H3 in Fig. 7, but further provision is also made for operating a switching system l2l thereby to connect the output of the power amplifier to any one or more mission of a communication. will, therefore, be'understood The circuit I23 to connect the may be operated localcontrol.

6 power when the station is not in use as a'relay station. Accordingly I preferably provide a re-\ lay I25 operable upon setting the station selector switch 80 in a mven position (following the position in which the switching systems Ill and I2! would be rendered operable) and when the station selector is so set the relay I25 becomes energized thereby to apply power from the battery iii to the power amplifier H0.

Fig. 9 shows illustratively a typical concatenation of relay stations A, B, C, D, E and F which are so associated that communications may be established between any two such stations. Where other stations intervene the communications may be relayed either one way or both ways, as desired. In connection with Fig. 9 it will be understood that any of the ements of my invention may be used as shown in the figures hereinbefore described. The M i for establishing communications as between difierent relay'stations have been fully described in connection with Figs. 7 and8.

As an alternative arrangement from that shown in Fig. 9 a cross-connectionbetween two different channels of communication may be established as shown at station E in Fig. 10. In this case station E is adapted to relay signals as between any two or more oi the outlying relay etc A, 0,!) and E, respectively.

From the foregoing description it will be apparent that my invention is adapted to a number of practical applications among which the following may be mentioned:

0. Establishment of. relay stations at airports or along the lines of aircraft travel so that communication to or from one or both ends of the relaysystem and to or from the aircraft can be carried. on, without danger of the aircraft being out of range of some station along the relay system. 1

2). Establishment of relay stations within or surrounding an area served by police radio and enabling two-way flexible communication with automotive police vehicles.

c. Establishment of communication with railroad trains either along the main line or in yards, including train dispatching.

(1. Establishment of short-range communication with river and harbor craft through a relay system around the harbor or along the river traversed. I

e. Establishment of means for injecting locally-picked-up signals covering events of interest into national broadcasting networks of the radio relay type. This is an important element in the practical operation of such a system.

Although I have shown in more or less detail a sufficient number of modifications of my invention so that the spirit and scope thereof may be appreciated by those skilled in the art, it will nevertheless be manifest that other modifications may well suggest themselves in view of this disclosure. The scope of the invention is, therefore, to be understood as being commensurate with the scope of the claims themselves.

I claim:

1. In a radio relay station, a plurality of directive and non-directive antennae, each adapted for alternative use for transmission or reception,

said directive antennae being orientable in suitable directions with respect to other radio stations, receiving and frequency changing apparatus connectable to certain of said antennae upon use thereof for reception, transmitting apparatus connectable to certain of said antennae upon :ensasci use thereof for transmission, said transmitting apparatus comprising an oscillator, a modulator and an amplifier, and remotely controlled selective switching means for feeding modulation energy irom at least one frequency changing apparatus unit to at least one modulator unit, thereby to relay a communication from station to stat on.

2. A relay station constituted as in claim 1 and having means for injecting modulations into at least one of said modulator units from sources other than and in addition to said directive antennae.

3. A relay station constituted as in claim 1 and having means for simultaneously broadcasting intelligence signals while impressing corresponding intelligence signals upon certain of said directive antennae for re-transmission thereof.

4. In a system of the class described, a plurality oi geographically spaced relay stations, receiving and transmitting antennae at eachstation at least one of said antennae being omni-directional and others of said antennae being of the ultra-short wave directional beam type, means for relaying intelligence-bearing radio signals received at said relay station, said means comprising an amplifier, 9. local oscillator, and arrangements for modulating the output of said local oscillator in accordance with the received intelligence signals, selective receiving apparatus connected to the omni-directional antenna, and means responsive to signals effective upon said receiving apparatus for establishing and maintaining a desired connection between any one of said directional antennae which serves as a receiving antenna and said means for relaying intelligence signals.

5. In a system of the class described, a plurality of geographically space/d relay stations, receiving and transmitting antennae at each station, at least one of said antennae being omnidirectional and others of said antennae being of the directional beam type, means for receiving intelligence-bearing radio signals on certain of said directional antennae, means comprising a frequency changing device, and an amplifier for utilizing said received intelligence-bearing signals and for retransmitting the same, and selective means for establishing and maintaining a desired connection between said re-transmittin apparatus and any desired selection of said directional beam antennae.

6. In an ultra-short wave relay station, the method or receiving and re-transnntting. intelligence which comprises simultaneously receiving at said relay station intelligence bearing signals such as are constituted by modulations of different carrier waves derived from respectively different outlying sources, combining said signals into a composite wave, amplifying said wave, separately filtering the modulated carrier components of said wave appropriate to the signals from each outlying source, and re-transmitting the energy so amplified and filtered in respectively different directions in accordance with the intended destination of each piece of intelligence.

7. A radio communication system comprising a plurality of static irective radio beam transmitting and receiving antennae at each station, means for fixedly aiming said antennae toward one another as between different pairs of stations, radio receiving apparatus connectable with the beam receiving antennae, means for combining and amplifying the modulated wave energy simultaneously received on difierent ones erable upon certain signals after of said beam receiving antennae at one of said stations from respectively different outlying stations, frequency selective means operable at each station for individualizing the intelligence signals appropriate to diiferent channels, and means for routing said intelligence signals from any desired receiving antennae through said combining and amplifying means to any desired selection of transmitting antennae.

8. A system in accordance with claim '7 and having an omni-directional antenna and a monitor receiver responsive to remote control signals, and switching means control signals for variably routing intelligence signals from certain of said receiving antennae through said combining and amplifying means to selected ones of said transmitting antennae.

9. A system in accordance with claim 7 and having remote control means whereby said amplifying means is variably adapted to deliver energy simultaneously to a plurality of selected transmitting antennae which are aimed in different directions.

10. A system is accordance with claim '1 and. embodying a remote control device operable upon said signal routing means at selected stations for producing a concatenation of communication channels from station-to-station, starting and ending at any desired points.

11. A system in accordance with claim 7 and embodying a remote controldevice simultaneously operable upon said signal routing meansat a plurality of selected stations for establishing a two-way communications channel which comprehends said selected stations in a closed loop.'

12. A looped arrangement of geographically spaced relay stations, each station having directive radio beam receiving and transmitting antennae suitably aimed in each direction toward sequential stations in the loop, remote control apparatus operable at each station for enabling said station to relay messages in and out on selected beams, radio apparatus connectable with different ones of saidantennae, said radio apparatus including a common amplifying means for simultaneously amplifying radio signals received from different directions, and means opoperable by said remote amplification for distributing the same independently and selectively to different transmitting antennae for re-transmission in desired directions.

13. A relay station having a plurality of directive antennae suitable for reception and for transmission of ultra-short waves, a single common power amplifier, a local source of oscillations feeding energy to said amplifier, selective means for feeding the output energy from said amplifier to any selected group of said directive antennae, a receiver responsive to signals derived from any other of said directive, antennae and a mixer device for modulating the energy from said local source in accordance with the received signals.

14. A relay station in accordance with claim 13 and having means for iiiterjecting signals into said mixer device from any desired source other than the directive receiving antennae.

15. A relay station in accordance with claim 13 and having means for broadcasting signals omnidirectionally while relaying the same directively.

16. A relay station having a plurality of differently oriented directive antennae suitable for reception and for transmission of ultra-shortwaves,- a single common power amplifier, means for combining the energies collected on difierently oriented antennae and feeding said energies to said common amplifier, an output circuit for said amplifier, a plurality of band pass filters connected to said output circuit, and means for feeding signaling energies of diflerent frequency bands from said common amplifier through respectively diifer'entones of said filters simultaneously and independently to each of a plurality of said transmitting antennae.

17. In a relay station, a plurality of antennae including antennae of the directive type, a power amplifier, frequency changing apparatus connected to said power enabling said power amplifier in cooperation with the frequency changing apparatus to impress different trains of simultaneously received sig nals after amplification and modification of their frequency characteristics upon respectively dif ferent ones of said directive antennae.

AIJ'RED N. GOLDSMITH.

amplifier, and means for 4a 

